The company trusts the potential for a positive overall survival readout in E2112, its Phase 3 registration trial of entinostat plus exemestane in HR+, HER2- breast cancer, and expects the next interim analysis in the second quarter, Morrison said.

He pointed out that a positive overall survival result would allow Syndax to file for full regulatory approval in an indication for which existing therapies have failed to show a survival benefit.

“In addition, we continue to expect to file an IND in the second quarter for our targeted therapy, SNDX-5613, an inhibitor of the Menin-MLL interaction. Preclinical data from our Menin inhibitor program has provided strong, consistent support for the therapeutic potential of this class in patients with genetically-defined acute leukemias, a disease area lacking effective options,” he said.

Syndax also reported in the announcement today that both ENCORE 602, the Phase 1b/2 clinical trial evaluating the combination of entinostat plus Genentech’s PD-(L)1 inhibitor, Tecentriq (atezolizumab), in patients with triple negative breast cancer (TNBC), and ENCORE 603, the Phase 1b/2 trial evaluating entinostat in combination with Bavencio (avelumab), an anti-PD-(L)1 co-developed and co-commercialized by Merck KGaA Darmstadt, Germany and Pfizer, in patients with ovarian cancer, failed to meet their respective primary endpoints of demonstrating an improvement in progression free survival (PFS).

With results across the entire ENCORE program now in hand, Syndax has decided to defer advancement of the entinostat-PD-1 combination program, including the previously announced ENCORE 607 registration trial in non-small cell lung cancer (NSCLC), the company said in the press release.

Syndax further said it will primarily focus its resources on advancing entinostat in HR+ breast cancer and SNDX-5613, a Menin inhibitor being developed for genetically-defined population of acute leukemias. Following availability of positive E2112 OS results, the Company will determine whether to advance its entinostat-PD-1 combination programs into one or more registration trials.

Dr. Morrison added, “While we are encouraged by ENCORE 601 entinostat-Keytruda® combination data in NSCLC and melanoma which suggests that entinostat has the ability to overcome resistance in PD-1 refractory patients, we believe that it is in the best interest of our stakeholders to prioritize our resources ahead of the E2112 OS readout, at which time we will make a determination on next steps for the I-O combination program. We are highly committed to advancing the balance of our pipeline programs, with an emphasis on our targeted therapy, SNDX-5613, and the E2112 registrational trial for HR+ breast cancer.”